Search results for "feature"
showing 10 items of 4091 documents
Remote sensing of cyanobacterial blooms in a hypertrophic lagoon (Albufera of València, Eastern Iberian Peninsula) using multitemporal Sentinel-2 ima…
2018
Eutrophy in Albufera of Valencia (Eastern Iberian Peninsula) is a quite old problem since after the intense eutrophication processes throughout the 1960s. The system shifted to a turbid stable state consolidated by the virtual disappearance of macrophytes by the early 1970s. The lagoon has been studied extensively since the 1980s, but efforts to revert the system to a clear state have not yielded the expected results because cultural eutrophication due to the growth of population in its area of influence and the effects of climate change, decreasing rainfall and increasing evaporation. This has driven to an increase in water retention times in the lagoon in recent years, resulting in a phyt…
Modeling belowground water table fluctuations in the Everglades
2010
[1] Humid lands, such as riparian zones, peatlands, and unsubmerged wetlands, are considered among the most biologically diverse of all ecosystems, providing a bountiful habitat for a large number of plant and animal species. In such ecosystems, the water table dynamics play a key role in major ecohydrological processes. The aim of the present study is to test with field data a recent analytical model for the estimation of the long-term probability distribution of the belowground water table position in groundwater-dependent environments. This model accounts for stochastic rainfall and processes such as infiltration, root water uptake, water flow from/to an external water body, and capillar…
Comparative Analysis Between France and Italy
2016
In this chapter, the role of river contracts in European and national water policies has been analyzed, by observing the two paradigmatic contexts of France and Italy. The comparative analysis undertaken both with respect to the experiences of water management policies and river contracts, allows to more deeply assess the governance processes of water resources and understand their political, legal and socio economic scopes. In addition, the comparison of these two national contexts has highlighted the opportunities for actual integration between practices of urban and territorial planning, and water management policies. The analysis has been specifically focused on the respective normative…
The Intervention of Hydrogeophysics in the Economics of Groundwater Exploitation and Management in Sicily
1989
Abstract The problem of the preservation of water resources in Sicily presents various aspects, some of which have been treated by a number of works. Among the different applied methodologies, the geophysical ones occupy an important place. Their contribution, directed to an economic and efficient exploitation and management of groundwaters, can be useful for selected “risk” areas as well as for more regional programmes. In fact, uncontrolled drillings on relatively rich aquifers occur in several zones of this island; the economically disadvantageous exploitation causes also heavy impoverishment and pollution phenomena. The fragmentation of charges and the lack of a planning Regional Body m…
Final Considerations and Open Scenarios
2016
European river contract experiences demonstrate a growing integration between these contractual agreements and the other instruments of water resources management, and urban and territorial planning. Therefore, river contracts represent innovative places for a new governance of river ecosystems and territories, also in compliance with subsidiarity principle. The twofold nature of these contractual agreements—technical dimension and concertative approach—together with their expected wide evolution, allow to identify river contracts not only as sectoral tools for water resource protection and management, but also as catalysts of a new culture of water, recalling the deep interrelationships ex…
Water stable isotope data set in temperate, lowland catchment, two years of monthly observations, River Salaca, Latvia
2020
Highlights • Two years of monthly water stable isotope ratios from temperate lowland catchment. • Hourly water table, temperature and electrical conductivity monitoring. • Distinct isotope ratios for raised bog, groundwater and rivers.
Mediterranean Climate and Eutrophication of Reservoirs: Limnological Skills to Improve Management
2011
Sicily is the largest Mediterranean island and one of the most densely populated areas in the region. To counteract the periodic oscillation in water availability and fulfill drinking and agriculture needs, about 30 dam-reservoirs, impounding in total 750 106 m3, were built in the last 60 years. However, the inherent features of the Mediterranean climate and the total lack of awareness from local authorities have contributed to a progressive increase in the trophic state of these human-made lakes. In particular, the water is stored during the winter rainy season and then it is intensively used in the dry summer. These operational procedures, in particular the time separation between filling…
Assessment and mapping the sensitive areas to desertification in an insular Sahelian mountain region Case study of the Ribeira Seca Watershed, Santia…
2015
10 pages; International audience; This paper presents the assessment and mapping of the Ribeira Seca catchment, an insular Sahelian mountain region sensitive to desertification, located on the island of Santiago, Cabo Verde. Desertification is a threat to the global environment, representing a serious ecological problem in Cabo Verde. To successfully combat desertification, an evaluation of desertification consequences is required and the building of cartography of the sensitivity for arid and semi-arid ecosystems is required as a first step. The MEDALUS model was the basis for this study in which six quality indicators were used: climate, soil, vegetation, land management, erosion and soci…
Prefiltering for pattern recognition using wavelet transform and neural networks
2003
Publisher Summary Neural networks are built from simple units interlinked by a set of weighted connections. Generally, these units are organized in layers. Each unit of the first layer (input layer) corresponds to a feature of a pattern that is to be analyzed. The units of the last layer (output layer) produce a decision after the propagation of information. Before feeding the computational data to neural networks, the signal must undergo a preprocessing in order to (1) define the initial transformation to represent the measured signal, (2) retain important features for class discrimination and discard that is irrelevant, and (3) reduce the volume of data to be processed, for example, data …
Hydro-Acoustic Target Detection
2014
This chapter presents an example of utilization of the discrete–time wavelet packets, which are described in Sect. 9.1, to classification of acoustic signals and detection of a target. The methodology based on wavelet packets is applied to a problem of detection of a boat of a certain type when other background noises are present. The solution is obtained via analysis of boat’s hydro-acoustic signature against an existing database of recorded and processed hydro-acoustic signals. The signals are characterized by the distribution of their energies among blocks of wavelet packet coefficients.